A bison steps through the steam of Yellowstone's Grand Geyser in an undated picture by U.S. photographer and video producer Ken Gunnufson, who says he stood just 20 feet (6 meters) from the animal.

"They say there is no such thing as luck," Gunnufson said in a statement. But his picture--with its uncanny combination of geyser eruption, unexpected cloudbreak, unhurried beast, and sunlight glinting off the animal's eye--may suggest otherwise.